Add documentation about the Docker judge

en/references/judges/docker-judge/index.md

@@ -0,0 +1,92 @@
+---
+title: "Docker judge"
+description: "Docker judge"
+order: 7
+---
+# Docker judge
+
+The Docker judge has 4 main functions:
+1. Check usage of Docker instructions like `USER` or `WORKDIR` using [dodona-containerfile-evaluator](https://github.com/Bond-009/dodona-containerfile-evaluator).
+2. Static analysis (linting) using [Hadolint](https://github.com/hadolint/hadolint) to annotate the code and optionally fail the solution if it contains errors.
+3. Build the submitted Dockerfile using [kaniko](https://github.com/GoogleContainerTools/kaniko).
+4. Check the existence and/or contents of files and directories in the image that is build from the submitted Dockerfile.
+
+Items 1 and 2 above are configurable.
+
+
+## Configuring Docker instructions
+
+Create a file called `judge.json` inside of the `evaluation` directory.
+Using this file it's possible to verify the base image, the `from` object requires the `image` to contain the image name, optionally a `tag` or `hash` property can be added to check the used tag or digest.
+It's also possible to check if the `USER` or `WORKDIR` instructions are used with the desired arguments.
+Another feature is the ability to check if the comments contain certain strings using the `comments` array.
+This file also contains a `files` property that is a JSON array of JSON objects.
+Each object contains a `path` property with the desired location in the resulting image.
+The object represents either a file or a directory, this is specified by the `type` property.
+Additionally objects representing files can also contain a `compare` or `regex` property.
+`compare` should be the name of a file inside of the `workdir` with which the file at `path` should be compared with.
+`regex` contains a ("extended") "regular expression that should match on the content of the file at `path`.
+
+An example `judge.json`:
+```json
+{
+  "from": {
+    "image": "alpine",
+    "tag": "3:20"
+  },
+  "user": "runner",
+  "workdir": "/course",
+  "comments": [ "docker run" ],
+  "files": [
+    { "type": "directory", "path": "/course" },
+    { "type": "file", "path": "/environment.yml", "compare": "environment.yml" },
+    { "type": "directory", "path": "/usr/miniconda3/envs/pipeline-tools-1.0.0" },
+    { "type": "file", "path": "/etc/os-release", "regex": "^ID=\"ubuntu\"$" }
+  ]
+}
+```
+
+## Configuring Hadolint
+
+The behavior of Hadolint can be modified by creating a [Hadolint configuration file](https://github.com/hadolint/hadolint#configure) with one of the following names inside of the `evaluation` directory: `.hadolint.yml`, `.hadolint.yaml`, `hadolint.yml` or `hadolint.yaml`.
+Using this it's possible to change the severity of annotations, fail when a certain severity is hit, check if labels exist and more.
+
+An example configuration file looks as follows:
+```yml
+no-fail: false
+failure-threshold: error
+label-schema:
+  org.opencontainers.image.title: text
+  org.opencontainers.image.description: text
+  org.opencontainers.image.source: text
+  org.opencontainers.image.revision: text
+  org.opencontainers.image.licenses: text
+  org.opencontainers.image.vendor: text
+override:
+  error:
+    - DL3049
+ignored:
+  - DL3004
+```
+
+`no-fail` specifies if the judge should fail the solution if the linter fails.
+`failure-threshold` sets the threshold for which rules will cause a fail, valid values are `error`, `warning`, `info` and `style`.
+`label-schema` is a dictionary where the key is the label name and the value of a label can be either of `text`, `url`, `semver`, `hash`, `rfc3339`, `spdx` or `email`.
+`override` is used to override the severity of rules, valid severities are the same as for `failure-threshold`.
+`ignored` is a list or rules that should be ignored.
+More configuration options can be found in the [Hadolint README](https://github.com/hadolint/hadolint#configure)
+
+
+## Limitations
+Due to the design of the judge it isn't possible to test the existence of files if no `COPY`, `RUN` or `ADD` instructions are present in the final stage.
+For example, if the following solution is submitted, a test for the existence of the file `/etc/os-release` which is present in the alpine base image will fail.
+```docker
+FROM alpine:3.21
+
+USER runner
+
+WORKDIR /home/runner
+
+LABEL org.opencontainers.image.title="test"
+```
+But once you add one of the instructions that can modify the filesystem this same test will succeed.

en/references/judges/index.md

@@ -20,6 +20,12 @@ C is a judge that uses the GTester framework to run tests on C exercises.\
 **Get started** [Documentation](https://github.com/mvdcamme/C-Judge), [examples](https://github.com/mvdcamme/C-Judge/tree/master/example_exercises) \
 **Created by:** [Maarten Vandercammen](mailto:mvdcamme@vub.ac.be)
 
+## Docker
+Docker is a judge that uses dodona-containerfile-evaluator, Hadolint, and Kaniko to evaluate Dockerfile exercises.
+**Programming languages**: Dockerfile
+**Get started** [Git repo](https://github.com/dodona-edu/judge-docker), [examples](https://github.com/Bond-009/dodona-docker-exercises) \
+**Created by:** [Lode Willems](mailto:bits@vib.be)
+
 ## Haskell
 Haskell is a judge that uses HUnit to test Haskell exercises. \
 **Programming languages:** Haskell\